Advantages and Disadvantages of File-Based CDS

File-based CDS store all information in single data files. This way, in most cases, a method file, which contains measuring and evaluation settings, and sequence file, defining the sample order of a measuring set, are stored together with the actual raw data files. These files are structured by a typical folder structure on the acquisition computer or on a network drive. For most users, this system gives the best 

The biggest problem of this technology is the missing possibility for administrating several versions of a data file in the same data system. Actually, this means that, for example, a modified method replaces the previous version when saved under the same name. The only solution to keep previous versions is to rename the method or to store it several times in different directories. Both practices can become rather unclear and there is a risk of mixing them up. 

With the increasing demands of laboratories in the regulated environment, further problems are faced data accessibility needs to be controlled and traceability for data generation and modification needs to be given. But a Windows file system does not offer solutions to a sufficient extent. Indeed, access rights can be assigned to folders and files. However, the implementation is too little sophisticated, the structure is uncomfortable, and administration is difficult. 

The idea of separating database and data files offers the chance of scaling up a CDS installation from a single PC, on which database and file server are installed together, up to global solutions, where database server and file server are installed on different physical devices. 

A further advantage of this technology is the simplified administration. Usually, data access is provided by the application itself and not by user definition. Sophisticated access rights on the data level are not necessary the application performs the access control. However, the mentioned benefits of a database-supported CDS are paid with some restrictions. For example, data backup and archiving of file-based systems is rather simple. Complete directories can be moved or burned on a DVD. Data that are required again, can be read directly from the storage medium. 

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